The present invention is directed to the field of cable installation, and more specifically to apparatus for manually separating a pre-slit pipe or other conduit of resilient material and inserting a flexible cable or other flexible line therein.
Tools for laying cable or other flexible line directly in the ground have long been known, as illustrated by U.S. Pat. No. 1,513,937 to A. Seidler, U.S. Pat. No. 2,692,092 to A. Kinsinger, and U.S. Pat. No. 3,561,222 to J. Sweeton, et al. However, in order to protect the cable or other line from damage due to exposure, it is often desirable to insert the cable or other line in a pipe or other conduit. The tools disclosed by Seidler, Kinsinger, and Sweeton et al. are not suitable for this purpose.
Other devices have been developed which are particularly applicable to installing fiber optic cable in a tube and which insert the cable into the tube through a slit in the tube. Examples of such devices are shown in U.S. Pat. No. 4,201,607 to Rautenberg et al. and U.S. Pat. Nos. 4,212,097 and 4,279,470 to Portinari et al. However, these devices are adapted for use in the context of a large-scale manufacturing operation employing automation to move the device relative to the tube, and are not suitable for on-site installation of the cable (i.e. installation of cable in a conduit in the ground or about to be placed in the ground).
It is a well known problem in the art of on-site cable installation that full reels of cable, particularly fiber optic cable, cannot be installed on-site in a conduit without the need for splicing the cable. However, splicing cable, particularly fiber optic cable, results in undesirable resistance. Previously, there were only two ways to avoid cutting and splicing the cable. The first was to mechanically split in half the pipe or conduit for the cable at the factory and rejoin it with nuts and bolts in the field, after the cable was inserted. Splitting the pipe or conduit has the disadvantage of requiring that the exact amount of pre-split conduit or pipe be ordered, shipped, and carried in stock. Moreover, the pre-split conduit or pipe is fairly expensive. The second way is through careful on-site design layout. However, a design layout which avoids the need for cutting and splicing the cable often cannot accommodate a change in plans. It is the solution of these problems to which the present invention is directed.